ceph/src/boost/libs/type_erasure/include/boost/type_erasure/is_subconcept.hpp

   1 // Boost.TypeErasure library
   2 //
   3 // Copyright 2012 Steven Watanabe
   4 //
   5 // Distributed under the Boost Software License Version 1.0. (See
   6 // accompanying file LICENSE_1_0.txt or copy at
   7 // http://www.boost.org/LICENSE_1_0.txt)
   8 //
   9 // $Id$
  10
  11 #ifndef BOOST_TYPE_ERASURE_IS_SUBCONCEPT_HPP_INCLUDED
  12 #define BOOST_TYPE_ERASURE_IS_SUBCONCEPT_HPP_INCLUDED
  13
  14 #include <boost/mpl/bool.hpp>
  15 #include <boost/mpl/not.hpp>
  16 #include <boost/mpl/if.hpp>
  17 #include <boost/mpl/end.hpp>
  18 #include <boost/mpl/find_if.hpp>
  19 #include <boost/mpl/has_key.hpp>
  20 #include <boost/type_traits/is_same.hpp>
  21 #include <boost/type_erasure/detail/normalize.hpp>
  22 #include <boost/type_erasure/detail/rebind_placeholders.hpp>
  23 #include <boost/type_erasure/static_binding.hpp>
  24
  25 namespace boost {
  26 namespace type_erasure {
  27 namespace detail {
  28
  29 template<class Sub, class Super, class PlaceholderMap>
  30 struct is_subconcept_impl {
  31     typedef typename ::boost::type_erasure::detail::normalize_concept<
  32         Super>::concept_set super_set;
  33     typedef typename ::boost::type_erasure::detail::get_placeholder_normalization_map<
  34         Super
  35     >::type placeholder_subs_super;
  36
  37     typedef typename ::boost::type_erasure::detail::normalize_concept<
  38         Sub>::type normalized_sub;
  39     typedef typename ::boost::type_erasure::detail::get_placeholder_normalization_map<
  40         Sub
  41     >::type placeholder_subs_sub;
  42
  43     typedef typename ::boost::mpl::eval_if< ::boost::is_same<PlaceholderMap, void>,
  44         boost::mpl::identity<void>,
  45         ::boost::type_erasure::detail::convert_deductions<
  46             PlaceholderMap,
  47             placeholder_subs_sub,
  48             placeholder_subs_super
  49         >
  50     >::type bindings;
  51
  52     typedef typename ::boost::mpl::if_< ::boost::is_same<PlaceholderMap, void>,
  53         ::boost::mpl::_1,
  54         ::boost::type_erasure::detail::rebind_placeholders<
  55             ::boost::mpl::_1,
  56             bindings
  57         >
  58     >::type transform;
  59
  60     typedef typename ::boost::is_same<
  61         typename ::boost::mpl::find_if<normalized_sub,
  62             ::boost::mpl::not_<
  63                 ::boost::mpl::has_key<
  64                     super_set,
  65                     transform
  66                 >
  67             >
  68         >::type,
  69         typename ::boost::mpl::end<normalized_sub>::type
  70     >::type type;
  71 };
  72
  73 }
  74
  75 /**
  76  * @ref is_subconcept is a boolean metafunction that determines whether
  77  * one concept is a sub-concept of another.
  78  *
  79  * \code
  80  * is_subconcept<incrementable<>, incrementable<> >             -> true
  81  * is_subconcept<incrementable<>, addable<> >                   -> false
  82  * is_subconcept<incrementable<_a>, forward_iterator<_iter>,
  83  *   mpl::map<mpl::pair<_a, _iter> > >                          -> true
  84  * \endcode
  85  *
  86  * \tparam Sub The sub concept
  87  * \tparam Super The super concept
  88  * \tparam PlaceholderMap (optional) An MPL map with keys for
  89  *   every non-deduced placeholder in Sub.  The
  90  *   associated value of each key is the corresponding placeholder
  91  *   in Super.  If @c PlaceholderMap is omitted, @c Super and @c Sub
  92  *   are presumed to use the same set of placeholders.
  93  */
  94 template<class Sub, class Super, class PlaceholderMap = void>
  95 struct is_subconcept : ::boost::type_erasure::detail::is_subconcept_impl<Sub, Super, PlaceholderMap>::type {
  96 };
  97
  98 #ifndef BOOST_TYPE_ERASURE_DOXYGEN
  99 template<class Sub, class Super, class PlaceholderMap>
 100 struct is_subconcept<Sub, Super, static_binding<PlaceholderMap> > :
 101     ::boost::type_erasure::detail::is_subconcept_impl<Sub, Super, PlaceholderMap>::type
 102 {};
 103 #endif
 104
 105 }
 106 }
 107
 108 #endif